Lite-03 audit M2: when a group's uni stream arrives for a
`subscribeId` whose subscription has already been removed (typical
case: listener canceled / unsubscribed before the publisher
observed it), the listener MUST signal the publisher to abandon
in-flight retransmits via `STOP_SENDING(applicationErrorCode)` on
that uni stream. Pre-fix, `drainOneGroup` silently dropped every
frame (`droppedNoSub++`) and let the publisher keep pushing until
natural FIN — wasted bandwidth on bytes the listener would discard,
plus relay queue pressure on the per-subscriber forward pipeline
that already sits behind the production stream-cliff.
Wire the latched `stopSending(MoqLiteStreamCancelCode.SUBSCRIPTION_GONE)`
on the first frame that observes `sub == null`. Latched (one-shot)
so concurrent frames in the same drain don't re-fire — RFC 9000
§3.5 says subsequent STOP_SENDINGs are ignored anyway, but it saves
the syscall and keeps the trace clean.
New error-code constant `MoqLiteStreamCancelCode.SUBSCRIPTION_GONE
= 0x10L` lives next to `MoqLiteSubscribeDropCode` in
`MoqLiteMessages.kt`. moq-lite leaves application error codes
undefined; we follow the same "small non-zero varint" convention.
Test seam: `ChannelWriteStream` is now a public class (was
private) with a `peerStopSendingCode` accessor, so a test that
holds the writer side (`serverSide.openUniStream() as
ChannelWriteStream`) can assert the listener's stopSending code
without racing for the peer-side `FakeReadStream` reference.
Regression test:
`MoqLiteSessionTest.listener_stopSending_group_uni_when_subscription_already_canceled`.
Audit doc: nestsClient/plans/2026-05-09-moq-lite-rfc-compliance.md (M2).
https://claude.ai/code/session_012TGfo99Ugz7fcCPv85a8Tq
Claude
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